Pressure-reducing valve for air-brakes.



No. 675,25. Patented may 28, |901.

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PRESSURE REDUCINE VALVE FOR AIR BRAKES.

(Appumxon med sept. la, i899.)

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No. 675,25I. Patented May 28, I90I. E. G SHURTT.

PRESSURE REDUGING VALVE FOR AIR BRAKES.

(Application med sept. 1s, 1899.).

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No. 675,25I. Patented May 28,1901.

E. G. SHOFPTT.v PRESSURE REDUCINGNALVE -FoR AIR BRAKES.

(Application led Sept. 1S, 1899.)

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(NQ Model.)

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No. 675,251. Patented may 2a, lem. E. s. suonTT.

PRESSURE REDUCING VALVE FDR AIR BRAKES.

(Application med sept. 1a, 1899.) (No Model.) 4 Sheets-Sheet 4.

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Miren STATES ATENT Fries.

EDWARD G. SHORTT, OF OARTHAGE, NEW YORK, ASSIGNOR TO THE INTERNATIONALAIR BRAKE COMPANY, OF JERSEY CITY, NEW

JERSEY.

PORESSURE-REDUCING VALVE FOR AIR-BRAKES.

SPECIFICATION forming part of Letters Patent No. 675,251, dated May 28,1901. Application filed September 13,1899. Serial-No. 730,299. (Nomodel.) y

To @ZZ whom it may concern:

Be it known that I, EDWARD G. SHORTT, a citizen of the United States,residing at Oarthage, in the county of .Ieiferson and State of New York,have invented certain new and useful Improvements in Pressure-ReducingValves for Air-Brakes, of which the following is a specification.

The invention relates to railway air-brakes.

Among the essential features of the present improvement are thoserelating to that class of equilibrio air brake valve mechanism known ashigh-pressure or high-speed train mechanism.

One principal, feature is adapted to act, after a full application ofthe brakes, to gradually reduce the braking power as the speed of thetrain diminishes, this for the purpose of permitting the application ofa high initial braking power and effecting the gradual reduction of thesame, as the momentum of the train is being overcome, to such an extentor in such manner that the skidding or sliding of the car-wheels willnot occur or for the purpose of adapting the braking power of a brakeapparatus to the braking work i-t is to do, such as braking an unloadedor a loaded car.

Another feature relates to improvements on the mechanism of -my UnitedStates Patent No.473,789,dated April 26,l892,which provides that the'airholding the brakes applied in the case of releasing the brakes of adisconnected or isolated car can be returned to the train-pipe insteadof bled to the atmosphere and the brake be repeatedly reset andreleased; and this present feature has for its object to insure that inmaking such release the exhaust valve mechanism will not be moved toexhaust the system.

' Other features that might be mentioned will be brought out in thedescription and claims.

In the drawings accompanying this specication I illustrate an equilibriobrake mechanism, together with my improvements for accomplishing withsuch mechanism the aboveset-forth eects.

By the term triple valve mechanism I mean one that acts to control thepassage of air from the train-pipe to the brake-cylinder, to eectbraking pressure on the brake-piston, and to release or overcome suchpressure.

In the drawings, Figure l represents a general diagrammatic view of anequilibrio airbrake mechanism embodying my improvements. Fig. 2 shows acentral longitudinal view of a brake-cylinder, auxiliary reservoir, anda form of triple valve mechanism controlling these parts. Fig. 3 is anend view of the same from right hand of Fig. 2. Fig. 4 is across-section of the same through the brake-cylinder. Figs. 5 and 6 areenlarged detail sectional views on plane a a of Fig. 9 of the valvemechanism for reducing the braking-application pressure and forequalizing same with the train-pipe, the valve handle and plug beingturned in Fig. 5 as shown by Fig. 9 and in Fig. 6 as shown by Fig. 10.Figs. 7 and 8 are sections of the valve casing and plug on planes b band c cof Figs. 5 and 6. Figs. 9 and l0 are enlarged end views similarto Fig. 3.

In referring to the views in detail, 1, Figs. 2 to 4, represents theexterior shell or casing of the reservoir and cylinder structure, whichis substantially square in cross-section and rectangular in shapelengthwise. 2 denotes the reservoir-space; 3, the angular spaces betweenthe brake-cylinder 4 and the walls l; 5 6, the brake-piston andpiston-rod, and 7 the head -plate which closes the structure and carriesthe neck 8, to which is secured the casing 9 of the triple valvemechanism, all as set forth in my Patent No. 538,547. l0 indicates theemergency-valve, and 1l the graduation-valve of the triple valvemechanism, and l2 is the piston thereof, 13 the trainpipe and train-pipespace on one side of said valve mechanism, 15 the passage from thereservoir to reservoir-valve 16, operated by piston l2 to put thispassage to communication with train-pipe space, and 17 the exhaust-portfrom the train-pipe, all as more fully set forth in my United StatesPatent No. 538,552, of April 30, 1895. 18 is the exhaust passage fromthe cylinder for either graduation or emergency actions, which leads tothe atmosphere independently of the trainpipe passage instead of throughthe same, as roo shown in the said paient, all as set forth and claimedin my copending application for Letters Patent, Iiled September 13,1899, Serial No. 730,298. 19 and 2O are the graduationpassages in thegraduation and emergency Valves, and 2l is the train-pipe-exhaustpassage in the emergency-valve. It is unnecessary to describe theconstruction of these parts with greater minuteness here, inasmuch asthey are presented simply by way of example or to illustrate one way ofpractically applying my present improvements.

Referring to Figs. 5 to 10, 22 denotes the casing of the valve forgradually reducing brake-application pressure after the brakes have beenapplied. 23 is the plug-valve of the same; 24, the handle attached tothe valve and by which it is turned, and 25 its seatingsprings. Thiscasing is secured to or made a part of the head 7 and is p rovided withthe passage 26, openly continuing through head of and to thereservoir-space 3, which passage is located to register with passage 27,piercing the plug-valve, and the latter with passage 28, extending tothe train-pipe space 13, while the valve-passage 29 is located to at thesame time register with the passage 30, extending to the brake-cylinderspace 4. In the same plane with passage 27 is located a passage 3l, Fig.S, which with the handle turned as in Figs. 6 and 10 registers withreservoir-passage 2G. Just above this passage 31 and opening thereintois located the seat of the pressure-retaining valve 32, thepressure-spring 33 of which is regulated by the screw 34. Above thevalve-seat and on plane c c, Fig. 6, the wall of the plug is pierced,Fig. S, by the passages 35 and 36, the former of which registers withthe train-pipe passage 2S and the latter with the cylinder-passage 30.It is to be noted that passage 29 is smaller in size and capacity forcarrying air than the passages 26, 27, and 28, and hence for thisadjustment of the valve air Will flow from the reservoir to thetrain-pipe in greater Volume than to the cylinder; also, that passage 35is smaller than is passage 36, and hence for this adjustment the volumeto the cylinder is greater than to the train-pipe.

Assuming that in running practice it is desired after full or emergencyapplication to gradually reduce the braking pressure as the speed of thetrain diminishes and to a point where it is practical to maintain auniform pressure on the brake-shoes, then the Valvehandle would be inposition of Figs. G, 8, and 10. Here it should be noted that under theseconditions and during graduation applications pressure from the cylinderand trainpipe would be maintained upon the retaining-valve 32, whichpressure, together with the retaining-spring tension, would suffice tohold the valve closed against reservoir-pressure. At the time ofemergency application, however, the air is practically all vented fromthe cylinder, and the retaining-valve is at once raised and begins todraft air 'from the reservoir into the train-pipe and cylinder, thevalve having been returned to its running position by the expansion ofthe abutting springs. Such air as goes into the trainpipe is saved andsuch as goes into the cylinder acts both by escaping from the reservoirand by pressure on brake-piston to reduce the braking pressure. When theair in the cylinder has reached a point of preponderating pressure overtrain-pipe pressure, the triple-valve piston and graduation-valve aremoved to graduate oi the excess by one or more movements and until thetension of the spring of the retaining-valve, together with the pressurecollected in the cylinder, overcomes the reservoir-pressure and holdsthe retaining-valve closed.

It is to be noted that the brake-actuating air is allowed to graduallyrelease or escape through the cylinder after application, that it isapplied (upon the brake-piston) to reduce the braking pressure, as alsoto help to close the retaining-valve, that a portion there- 01": issaved in the train-pipe and a portion in the cylinder, and that onlysuch amount is let to atmosphere as is necessary to continue the actionof transferring the pressure from the braking side of the brake-pistonto the opposite side or to the train-pipe until the retaining-valve beclosed, thus also maintaining the triple Valve in running condition.Thus the air released to reduce braking pressure is utilized not aloneto help by its pressure to overcome the braking pressure, but also torecharge the system and while the brakes are still on.

During application action if reservoir-air escape by the brake-pistoninto the cylinder the graduation-valve will discharge it, and thusprevent any creeping oi of the brakes.

Assuming the case of a disconnected or isolated and braked car and ofcourse that the train-pipe ends thereof are closed, the moving of thehandle of the valve to the p0- sition of Figs. 5, 7, and 9 will causethe braking pressure to become equal on both sides of the brake-piston,the air flowing faster to the train-pipe than to the cylinder, and thusinsuring the triple-valve piston remaining in running position-that is,not moving to either graduation or emergency position. After suchrelease the brakes can again be applied by opening the train-pipe, say,by using an angle-cock as though it were an engineers Valve.

Vhat I claim as new isl. In a fluid-brake mechanism, a pressureretainingvalve controlling passages extending from the operative face of thebrake-piston to its opposite face, one leading to the train-pipe and oneto the reservoir, and acting after brake-application action to reducethe pressure el the application-air by withdrawing it from the activeface and applying it to the other. A

2. In a fluid-brake mechanism, a pressureretaining valve, controllingpassages extend- IOO IIO

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ing from the reservoir and one leading to the train-pipe and one to thebrake-cylinder, Whereby after application action the reservoir-air isWithdrawn to the cylinder and train-pipe.

3. In a fluid-brake mechanism, a pressureretaining valve controlling anexhaust-passage from the reservoir and acting to partially exhaust thesame after application action,said valve being normally held seated byaspringand by train-pipe pressure.

4:. In an equilibrio fluid-brake mechanism a pressure-retaining valvecontrolling an exhaust-passage from the reservoir and acting topartially exhaust the same ai' ter application action, said passageextending to and being also controlled by the graduation-valve of theexhaust-valve mechanism, and a cock containing the pressure-retainingValve.

5. In combination in a fluid-brake mechanism, and with the train-pipe,exhaust-valve, brake piston and cylinder, and auxiliary reservoir,apassage-provided plug-cock and retaining-valve-controlled passagesextending through the said cock from the reservoir to the brake-cylinderand to the train-pipe, for the purpose set forth.

6. In a Huid-brake mechanism, retainingvalve-con trolled passagesextending from the reservoir to the brake-cylinders and to thetrain-pipe, the passage to the train-pipe being larger than that to thecylinder, for the purpose set forth.

7. In a fluid-brake mechanism an exhaustpassage from the reservoir to acock acting to open said passage in one position of its adj ustment to apassage containinga pressureretaining valve, and acting in anotherposition of adjustment to open said passage to a relatively smallpassage to the brake-cylinder, and to a relatively larger passage to thetrain-pipe, for the purpose set forth.

8. In combination in an equilibrio airbrake mechanism and with theexhaust-Valve mechanism, brake-piston, and the chamber thereof, meansacting after brake application to withdraw the brake-application air onone side of the piston to the other side thereof and to the train-pipe,and to opposite sides of theexhaust-yalve piston to cause the same to beheld in normal or running condition.

In testimony whereof I affix my signature in presence of two Witnesses.

EDWARD G. SIIORTT.

Witnesses:

MILTON CARTER, E. D. EAMES.

